The electrical conductivity of a vapor grown carbon fiber (VGCF) enhanced polymer was found to be 12 orders of magnitude greater than the conductivity of a SWNT-enhanced polymer. These results lend support to the belief that the VGCF remained more or less structurally intact during the in-situ polymerization and work-up, whereas the SWNTs may be breaking down under the polymerization conditions.
3-Phenoxybenzoic acid was bound to a vapor grown carbon nanofiber (PR-19-HHT) through the formation of a keto-carbonyl linkage. This monomer was then polymerized via a Friedel-Craft acylation in the presence of poly(phosphoric acid) to form high molecular weight poly-(oxy-1,3-phenylenecarbonyl-1,4-phenylene) or mPEK.
The 10 weight % sample was dissolved in MSA and a film cast on a quartz-casting dish at 85oC in vacuo for conductivity measurements. The dc electrical conductivity was measured by the standard 4-point probe method and was found to be more than 12 orders of magnitude greater than the conductivity (~1x10-14 S/cm) of the composite fiber derived from rigid-rod poly(р-phenylene-benzobisoxazole) and SWNT (PBO/SWNT; w/w 90/10), prepared via in-situ polymerization in poly(phosphoric acid). This may be due to the SWNTs breaking down under the polymerization conditions.
Top table: Thermal properties of mPEK-g-VGCNF samples. There is excellent agreement between the theoretical and experimental values. These results lend support to the belief that the VGCNF remained more or less structurally intact during the in-situ polymerization and work-up.